1. Field of the Invention
The present invention relates to an optical part linkage device that is formed by linking two parts, each of which holds an optical device, through a threaded mechanism, and an optical module using the optical part linkage device.
2. Description of the Related Art
For example, in an image pickup optical system, such as a camera system, a lens barrel that holds an image-forming device (lens) and a holder that holds an image pickup device, such as a CCD (charge coupled device), are provided as separate parts, and the lens barrel and the holder are constructed so that they are linked by a threaded mechanism in order to position the lens of the lens barrel (that is, adjust the location of the focus) by the threaded mechanism. After the location of the focus is adjusted, the lens barrel is positioned with respect to the holder in order to fix the location of the lens. Hitherto, the lens barrel and the holder have been secured by using an adhesive or a spring washer.
However, in the methods of securing the lens using an adhesive and a spring washer, when a threaded section is loose (that is, when an external thread and an internal thread are loose with respect to each other), a shift occurs from the focal location during bonding with an adhesive. Therefore, there may be cases where the location of the focus cannot be adjusted with proper precision. In the method of securing the lens using an adhesive, the step of hardening the adhesive (including UV (ultraviolet) illumination) and the like need to be carried out, thereby resulting in the problem of increased costs.